#1143458 jline3: CVE-2026-56740 CVE-2026-56741

Package:
src:jline3
Source:
src:jline3
Submitter:
Salvatore Bonaccorso
Date:
2026-08-06 17:37:03 UTC
Severity:
normal
Tags:
#1143458#5
Date:
2026-08-02 07:04:37 UTC
From:
To:
Hi,

The following vulnerabilities were published for jline3.

CVE-2026-56740[0]:
| JLine is a Java library for handling console input. Prior to
| 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet
| module does not limit the number of environment variables a client
| may inject via the Telnet NEW-ENVIRON option, and
| TelnetIO.readNEVariables() in TelnetIO.java:1127-1180 stores each
| variable pair in a HashMap held by ConnectionData, allowing an
| unauthenticated attacker to flood unique variable pairs before the
| terminating IAC SE byte and exhaust JVM heap memory with an
| OutOfMemoryError. This issue is fixed in versions 3.30.14, 4.0.16,
| and 4.2.1.


CVE-2026-56741[1]:
| JLine is a Java library for handling console input. Prior to
| 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet
| module does not apply an upper bound to terminal dimensions received
| via the Telnet NAWS option, and TelnetIO.handleNAWS() in
| TelnetIO.java:856-879 reads client-supplied width and height as
| 16-bit unsigned integers and passes values such as 65535x65535 to
| setTerminalGeometry(), allowing an unauthenticated remote attacker
| to repeatedly alternate values and trigger continuous expensive
| rendering work that causes CPU exhaustion and denial of service.
| This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.


If you fix the vulnerabilities please also make sure to include the
CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-56740
https://www.cve.org/CVERecord?id=CVE-2026-56740
https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f
[1] https://security-tracker.debian.org/tracker/CVE-2026-56741
https://www.cve.org/CVERecord?id=CVE-2026-56741
https://github.com/jline/jline3/security/advisories/GHSA-2r2c-cx56-8933
[2] https://github.com/jline/jline3/pull/2000

Regards,
Salvatore